The use of LED lamps is a trend that continues and as the technology matures, it is expected that LED lamps will be the predominant source of artificial light for general illumination purposes. LED lamps are robust solid state devices capable of lasting 50,000 hours or more. The main electrical components of existing LED fixtures are the LED module comprising LED lamps organized in arrays and an electronic driver. The driver is a complex device used to control the voltage and current applied to the LED arrays based on high frequency switching of power electronics devices. The buck and boost converters are typical topologies of existing LED drivers. Because of the complexity of these drivers, they are usually the weakest link in the LED lighting fixture system, limiting the expected life and output of the existing fixtures. Additional disadvantages of the existing LED drivers are, the over sizing of the LED lighting fixtures in order to house the relatively large driver units, lower energy efficiency, and higher cost of the LED lighting fixtures among others.
The prior art proposes to control the current of LED arrays by changing the configurations from series to parallel and vice versa. However, the solutions disclosed by the prior art are still not practical and of low commercial value. First, when the proposed regulation scheme maintains a constant current, some LED lamps are turned off making it not suitable for DC applications. On the other hand, when the solution scheme is to maintain a constant illumination level, the current of the array varies in a wide range generating higher amount of harmonics and increasing the design constrains of the driver.
There still is a market need for an LED lighting fixture with a minimum amount of electronic components to drive the LED arrays at lower switching frequencies and with improved current-illumination regulation and efficiency performances. Furthermore, in addition to increasing the efficiency and life expectancy at a lower cost, the electronic components can be integrated with the LED modules substantially decreasing the footprint of the LED fixtures.